This morning I powered on my computer like any other day only to get a DrMOS overheat warning pop up. I built this system on November 16th and it's been running fine until today. I had it overclocked until about last week when I decided I'm not doing anything that really needs an overclock at the moment, and brought it back to default settings. Last night I played some games (WoT and BF:BC2) for a little bit later into the night than usual, but nothing that would stress anything on the system.

I read that clearing the cmos might help, but it hasn't in my case. I am running the latest bios for my motherboard.

That fast? Sounds like your CPU heatsink might have came loose. Check to make sure all 4 secure points of the heatsink are still securely fastened to your motherboard. If they are all fastened, try removing the heatsink and clean off the old thermal paste, and apply new thermal paste. Then reseat the heatsink and see if that helps.

It would be really odd if the thermal paste is the problem though. Your computer isn't that old.

That fast? Sounds like your CPU heatsink might have came loose. Check to make sure all 4 secure points of the heatsink are still securely fastened to your motherboard. If they are all fastened, try removing the heatsink and clean off the old thermal paste, and apply new thermal paste. Then reseat the heatsink and see if that helps.

It would be really odd if the thermal paste is the problem though. Your computer isn't that old.

I believe things have gotten worse. After reseating the cooler, I powered on the system and it shut down immediately. It powered up again on its own, then there was a crackle and pop. It tried once more on its own, but I pulled the plug to prevent any further damage.

This is my first homebuilt pc. I had some experience with my old desktop, plus tons of help from my friends who build their own. I spent months scouring the web for building advice before I built this computer. I take every precaution when working with hardware. It's too expensive not to.

Now, RMAing the motherboard makes sense, but why the CPU? Just to be safe?

I would investigate the source of the "pop" if possible, especially if there was smoke involved (not that it was mentioned). Could have been a faulty MOSFET on the motherboard, as boards or video cards usually instantly turn off when a voltage regulator problem occurs. I had a GTX 460 short out on me (found the system off and wouldn't turn on) so after cycling the power supply a few times and getting split second power-ups, I pulled the video card and the board ran fine on the integrated graphics. Put the GTX 460 back in, system powered on and the voltage controller IC on the video card caught on fire.

Zero to Facebook faster than it takes me to make a sandwich, which is good enough for me.

+1 for RMA

When you un-overclocked, did you clear CMOS/load defaults or just remove the overclock via settings? It's usually best to reset to defaults and re-apply the settings you prefer than potentially forgetting to reset something such as voltage.

I don't think it's a coincidence that it died shortly after un-overclocking it. Sounds like you missed a setting. If you lost a VRM, I think the chances of your CPU being fried are good. If you have a bit of time, I'd take the motherboard out and look over it for any scorch marks.

If you suspect the PSU, give it a sniff. You can test it without a load by unplugging everything, taking a wire/paperclip and shorting out the green wire to a black wire on the 20/24-pin ATX power connector. Once the PSU is running, check voltages with a multimeter. This isn't ideal since what we really care about is voltages under load, but it's a good start. Also, it's generally not recommended to keep a PSU running with no load for very long.

If a PC shuts down in the first few seconds on boot, it'd be a bad idea turning it back on without checking your heatsinks.

Good luck getting it fixed though. The last system I had explode on me was my old Athlon XP rig. The power supply went and took out the motherboard and CPU. Had to fall back on a P3 Celeron eMachine and it was terrible.

I believe things have gotten worse. After reseating the cooler, I powered on the system and it shut down immediately. It powered up again on its own, then there was a crackle and pop. It tried once more on its own, but I pulled the plug to prevent any further damage.

I doubt anything could have been done to prevent it if it was the motherboard's fault. The GTX 460 I mentioned caught on fire about 6 months after purchase, when the 4 other GTX 460s I own are still working fine at the same clocks and voltages.